A friend of mine bought me a fountain pen for my birthday. I expected to have it sit in my standard pile of pens, but no. I love that thing. I'd never have bought a fountain pen otherwise.

I've since purchased an inexpensive Muji pen. It comes with garbage ink, but I replaced that with a refillable cartridge and Parker ink. It's now my second favorite pen. (I say this simply to indicate that it doesn't have to be an expensive fountain pen.)